Every boy dreams of it: growing up to be the youngest man by several decades at cardiac exercise rehabilitation. So I found myself, at age 23, gathering three times a week with about a dozen retirees in a medical gym atop a hospital skyscraper to exercise under strict supervision and monitoring. 

I had lived independently for five years in New York, and the lifelong serious heart disease I walked around with had stayed manageable all that time. My disease had been much worse before moving here, and had only been a minor factor since, with the occasional pacemaker replacement or medication change.

I had moved to the city to do the usual things on offer to 18-year-olds: to attend college without a campus, to live a version of city life that only existed in a TV show I didn’t like, to build a thick divider between an unpleasant childhood and a more engaging future. But I hadn’t planned for this — standing in a cold, clinical exercise room full of seniors where I looked more like a grandson with a driver’s license than a patient myself. 

Our crimes were various health catastrophes: heart attacks, bypass surgery, strokes. I’d done time at cardiac rehab before, years prior, for a general lack of cardiovascular capacity, but this, my second round, resulted from an emergency episode of ventricular tachycardia. VT is a kind of arrhythmia where the heart appears superficially to be beating incredibly fast, but is actually not really beating at all: only the ventricle pumps, and if nothing is done, cardiac arrest soon follows. For me, defibrillation followed, then a number of complex procedures, and then in something close to a permanent solution, I had surgery to implant an ICD. 

An ICD is a premium pacemaker (think of it as a two-in-one bundle) and it stands for “implanted cardiac defibrillator,” the main extra feature being the ability to shock the heart if it ever falls spontaneously into similar kinds of arrhythmias. It’s very Magic School Bus, a little bit Honey, I Shrunk the Defibrillator — “What if we put the hospital inside the patient?”

My doctors had concluded that an arrhythmia could happen again at any moment, and thus the permanent micro paddles stitched onto my heart. If my heart rate spiked above 170 bpm, the device would discharge a shock in 30 seconds. If it spiked above 200 bpm, the device would zap me instantly. The only warning I’d receive, aside from feeling the arrhythmia, would be some kind of pre-programmed tone pinging from within me like a siren.

Starting with the emergency episode, my hours had been occupied by the constant fear of recurrence. Every ounce of expended energy could raise my heart rate and threaten another emergency. I moved slowly, carefully, through life as if trying to evade a grid of invisible lasers.

I wouldn’t take the subway unless accompanied by a friend, afraid something would happen while alone underground and without a phone signal. I tried to avoid stairs, but I lived at the top of a walk-up, which made it easier to never leave my apartment. At first, I was forbidden from exercising because it could instantly kick off another arrhythmia. But given that physical activity was part of the treatment for my underlying condition, my doctors would want me to begin exercising again relatively soon. 

I was never fully dressed until my forefingers were pressed hard into my neck, and I walked around the world like this, looking like a man struggling to hold up his own head. And because one debilitating fear is never enough, once the ICD was in place, the threat of the problem was joined by the danger of its solution. If another arrhythmia set off, what would happen? Would I die (regrettable, scary) or would I be rescued by something even more terrifying: an internal, autonomous high-energy electrical shock?

At exercise rehab, my fear was indulged at comical scale: clusters of flat-screen display monitors hung at four intervals throughout the room, towering over us like leaderboards. If someone’s heart rate was climbing too high, or one of the nipple-like stickers had detached from skin and clung to the inside of someone’s shirt, everybody knew. Alarms sounded gently and one of the nurses would glide over to the patient to figure out the cause. While my elder classmates failed to keep their jogging khakis out of the cycling gears, I kept my eyes fixed to the screens, waiting for the slightest shift in the steady wave representing my pulse. 

My mortal phobia of my own heart rate lessened as I reached one month, then two, in the program. But just as I made progress through safe and controlled physical activity, that very same security became a ceiling. The insurance of having a perfect read of my pulse didn’t follow me through the rest of the world. Imagining exercising alone and unmonitored, the fear spiked again. I needed, or believed I needed, some ability to constantly know my pulse, and a quick search took me to all the companies happy to sell me a solution. 

First came the Apple Watch, which had a basic heart rate tracker buried under its suite of other features I couldn’t imagine using. At different levels of customization, the price approached the cost of a brand new smartphone. I’d privately vowed years earlier never to get one, owing to the fact that they, like most tech watches, looked goofy, but also because I hated on principle Apple’s attempt to monopolize every surface of the body. They were in our pockets, our ears, now on our wrists, and once Google Glass had faded from collective memory, I was sure they’d next be on our faces. 

Then there were many secondary options, mostly cheaper at least, an assortment of companies with somewhat familiar names and their wrist-bound Activity Trackers and Fitness Bands and Running Sensors. They didn’t promise to tell me the weather or store my passwords or check my texts. Each was uglier than the last. They were painted in bright, whimsical colors or had big, blocky faces, or both, as if their ideal customer was someone trying to remotely hack into Willy Wonka’s chocolate factory. They could all technically get the job done, but even ignoring the fashion, something within me was resisting them out of hand. 

Eventually, I found the FitBit Alta HR. The HR stands for “heart rate” and, mercifully, that was all it tracked. It was a slim black wristband with a narrow black face, closer to the rubber charity bracelets that dominated the wrists of the early 2000s than the arm-bound supercomputers walking around now. It cost $149 plus tax, which was more disposable income than I had at the time, given that I hadn’t been working for months. I was still on my parents’ health insurance, and they were covering all of my health expenses, so they offered to buy it for me. I was (and am still) lucky and fortunate for this, to even have the option to solve this problem.

Even so, the purchase felt extravagant and unnecessary. It was health care that wasn’t, medicine from a company that now, three years later, is in the process of being acquired by Google. As with so many purchases, it prompted me to wonder if this was something I needed, or if I was just a reliable mark.

I wore the bracelet to exercise rehab. I conducted my own product reliability test, measuring the accuracy of the FitBit’s heart rate reading against the medical monitor. Surprisingly, the two numbers were often the same, or at least within a point or two of each other. 

The FitBit couldn’t do anything more complicated than tell me my current heart rate or show me the time. It couldn’t provide a more complicated ECG readout like a medical heart monitor does, and it couldn’t decipher more complex heart functions or tell if I was experiencing an arrhythmia.

The bracelet simply read the pulse in my wrist and translated it to a number, just as I’d been doing manually for the months before, so in effect, I had paid to outsource the same work I had already been doing to a machine. Call it a placebo, maybe, but just knowing the FitBit was able to perform this simple job with near-accuracy made me less anxious about exercising without medical supervision. In comparison to the real thing, the device was capable of only the bare minimum — yet, somehow, that felt like enough. 

When the tachycardia happened, I had been alone. It started with a galloping in my chest that did not end, then a pain from the galloping, then panic. I turned to my wrists and my neck for the answers, and found nothing. Total silence. This is what happens when a heartbeat, which is a cycle of blood movement, does not complete. In the back of the ambulance, surrounded by EMTs, I was even more alone. Wanting only to be with family and the people I loved, the presence of strangers made the distance between us more obvious. They put the defibrillation pads on to me — one on the chest, one on the back–and started up the machine.

I asked the woman sitting closest to me if she would hold my hand, so I might be slightly less alone, but she couldn’t. “We can’t touch you,” is actually how she said it. In seconds, I would be electrically charged, a human conductor. My own physical touch had never been so dangerous.

In that moment, I was acutely vulnerable in a way I had never experienced. And in the months after, I became so cautious that, to avoid even the possibility of raising my heart rate, I was at risk of never doing anything again. Having the FitBit was a form of safety net, an approval to dangle one foot over what I perceived as the edge. It also externalized what had been a firmly internal problem. Like trying to see one’s own face without a mirror, my heart was frustratingly out of reach. It was inside me, yet it functioned totally independent of me. Visualizing my heart rate gave me a sense of control that, while completely false, allowed me to wrest back the authority I had ceded to it. 

It began a cycle: after the class ended, I started exercising on my own again. I wore the FitBit to the gym, and then when I felt ready to go places that weren’t the gym, I wore it there too. It allowed me to be more active, and the more time that I spent active, the less nervous I became.

Time passed, and I stopped wearing it out in daily life, feeling comfortable enough to go to dinner with a friend or see a movie without constantly checking my pulse. Eventually, I found myself at the gym without the instinct to check it there either, and became annoyed more often at the rubber sticking to my wrist than I was afraid of lingering death. The FitBit moved to its next home in a desk drawer after maybe six months of use. 

Having used it until I didn’t need it, my relationship with the FitBit had a purity not normally found in our uses of tech. Commercial tech is designed for addiction; companies encourage lifelong engagement by constantly adding features to their products so you have to keep buying the next available model. This has always bothered me about the integration of wellness into consumer tech products. Medicine, ideally, is supposed to be an engineer of its own obsolescence. Good medicine heals you to a point of health, and then lets you be. Of course, modern private medicine and its failures in disease prevention hardly does that either, but wellness tech has eliminated all pretense.

Instead, it wants you to build its products into your life like habits, make daily practices and develop healthy regimens, angling to meld with your idea of your own survival so totally that you think of abandoning one of its products like you’d think of quitting a medication cold turkey. By arming iPhones with step counters and selling watches that promise to help your sleep patterns, tech companies cover their more insidious goals by appearing to serve public health, and they give us readymade justifications for our own purchases. 

The FitBit also happened to come along when I was just getting used to a new piece of technology I had no say in adopting. The ICD was a permanent and unpleasant development in my history with medical tech. Here was a device that couldn’t prevent arrhythmias, only try to stop them once they’d begun. Much like most consumer tech, it was a solution waiting for a problem. I hated it, but I needed it.

But I could dictate the terms of my relationship with the FitBit. I decided if and when I wanted to use it, and more importantly, I could decide when I was done with it. If I were a real person (not an actor!) inside a commercial, I would, reluctantly, tell the truth: This product gave me my life back. And I never want to see it again. 

Jameson Rich is a writer and video producer in New York, where he is trying not to check his pulse.